1. Field
The present disclosure relates generally to manufacturing and in particular, to a method and apparatus for drilling holes in objects. Still more particularly, the present disclosure relates to a method and apparatus for adaptively drilling holes in objects with different types of layers.
2. Background
Manufacturing may involve the use of tools and/or labor to create items for use or sale. In aerospace manufacturing, these items may include, for example, without limitation, aircraft, aircraft parts, missiles, rockets, and/or spacecraft. In manufacturing various items, a number of different operations may be performed. These operations may include, for example, without limitation, extrusion, pressing, rolling, piercing, machining, drilling, routing, and curing.
With respect to drilling, a drill may be used to create holes or channels that may be cylindrical in solid materials. A drill may be a tool with a rotating section that may hold a drill bit to drill holes. A drill bit may be a cutting tool that may be used to create holes in an object. These holes may be cylindrical or non-cylindrical depending on the particular implementation. Drilling may involve drilling a channel, such as, for example, without limitation, a cylindrical hole.
One type of drill that may be used for drilling holes is a drill with a positive feed feature. This positive feed feature may allow the drill to push the drill bit into the object, while drilling occurs. Drills also may have a peck and feed feature used to push the drill bit into the object and then retract the drill bit while drilling occurs. This type of forward and reverse motion of the drill bit may provide for a cleaner quality hole. Further, this type of drilling also may reduce the amount of heat applied to the object, which also may increase the quality of the hole. Also, this type of drilling may reduce erosion in a carbon fiber reinforced plastic when the carbon fiber reinforced plastic is the first layer and titanium is the second layer.
Currently available drills may include, for example, without limitation, pneumatic drills. Compressed air and an air valve may be used to rotate the drill and move the drill forward and to retract the drill. This type of drilling is also referred to as a “peck feed” or “peck and feed” process. With the forward and reverse movement of the drill bit, air valves are used to shift the direction of the airflow back and forth to move the drill bit forward and backward within the hole.
This type of drilling may be performed into an object containing layers of different types of materials. These layers of different types of materials may be referred to as a stackup. These different layers may have different levels of hardness that may require different drilling speeds. For example, a stackup may include a layer of carbon fiber reinforced plastic (CFRP) and a layer of titanium. The titanium layer may be harder than the carbon fiber reinforced plastic layer. The titanium layer may require a drilling speed and/or feed rate that is slower than that for the carbon fiber reinforced plastic layer.
Currently, positive feed drilling of a stackup containing different layers may be limited in speed and/or feed rate by the hardest layer in the stackup. Physically, the carbon fiber reinforced plastic layers in a stack may be, for example, without limitation, two times the thickness of the titanium layers within the stackup. When performing drilling operations based on the speed and/or feed rate for the titanium layers, a considerable amount of time may be wasted in drilling the carbon fiber reinforced plastic layers at the slower speeds.
Therefore, it would be advantageous to have a method and apparatus that overcomes the problems described above as well as other problems.